Evaluate a 1-Variable Expression

Evaluate Expressions: Learn

A mathematic expression is a group of numbers and
operators which can be evaluated to determine their value.

There may be a variable in the expression which
represents a number that may or may not be known. A variable
is simply a symbol used as a placeholder for the unknown
number. Mathematicians frequently use "x" as the variable,
but it could be anything, such as any letter of the alphabet,
or even a smiley face drawing.

If we know the value of the variable, we can find the value of the
entire expression.

For example, if x=3, then the expression 7x+4 can be evaluated
in the following way:

7x+4
=7*3+4
=21+4
=25

The very first step where x is replaced by its value is called
substitution.